The present invention relates to an improvement in an apparatus for controlling the arrival of an elevator at a given elevator floor.
It is well known in the art that a floor selector may be used in a multi-story building for instructing the destination direction of an elevator cage or a target floor to be stopped by registering a floor calling and a cage calling.
Since microcomputers have recently been introduced a multi-story building floor selector which employs a microcomputer has been proposed. This selector operates as indicated below:
(1) A pulse is generated every time the elevator cage runs a predetermined distance.
(2) The above-described pulse is added or subtracted according to the running direction namely the upward or downward direction of the cage, and the present position of the cage is calculated from the number of pulses relative to a given reference position.
(3) The number of pulses for each floor in a plurality of floors to be stopped at is prestored in a memory.
(4) A position which is calculated in advance-according to the rated speed of the cage and which is prestored in the above-described memory (and hence the floor position which precedes from the position of the cage) is outputted from the memory and is calculated as the preceding position to decelerate and stop the cage with respect to the elapsed time after the cage is started.
(5) When the cage is called from a floor which is within the range of the preceding position (when the number of pulses for the floor from which the cage is called coincides with the preceding position), the deceleration of the cage to this target floor is determined.
(6) When the deceleration is determined, the number of pulses for the floor from which the cage is called and the remaining distance from the present position of the cage calculated in the above step (4) to a target floor to be stopped are calculated, and a deceleration instruction value corresponding to the remaining distance is produced.
However, if in step (1) or (2) the pulse count is erroneous, and the position of the cage is erroneously detected (heretofore termed as a "detection displacement") the deceleration of the cage is not carried out for the proper position, and the remaining distance which is calculated in step (6) becomes incorrect. Accordingly, the deceleration instruction value corresponding to the remaining distance gradually decreases not towards the actually existing floor but towards a position where no floor exits. In other words, if an erroneously detected target position for the cage to be stopped is produced and if the actual floor position is ahead of the erroneous target position, the cage approaches the actual floor with a deceleration instruction value lower than the proper value. On the other hand, if the actual floor position is located after the erroneously calculated target position, the cage approaches the actual floor with a deceleration instruction value higher than the proper value. Further, in both cases, an abnormal speed detector is operated to produce an abrupt stop instruction, the cage is thus stopped at an intermediate position between adjacent floors, and passengers in the cage are trapped in the cage.